Abstract: Using field and laboratory datasets obtained from five cruises of Taihu Lake in 2011, the relationships between particulate organic carbon (POC) and coefficients of particle absorptions and backscattering were examined to evaluate the impact of POC assemblages on the inherent optical properties in eutrophic inland water. The results showed that concentrations of POC varied greatly in Taihu Lake among the five cruises, ranging from 1558.06 to 5281.09 mg/m³. There was a strong relationship between POC concentrations and particle absorptions, especially in the wavelengths, where absorption was dominated by phytoplankton pigment concentrations (605-700 nm), with Pearson's correlation coefficients higher than 0.9 in all the sampling champions. However, a weak correlation between POC and particulate backscattering coefficient, b_bp (510), was observed (R²=0.04, P=0.02). The influence of POC on the particle absorptions due to phytoplankton pigment and detritus was illustrated, with POC highly correlated with phytoplankton absorptions (R²=0.82) and poorly related to detrital absorptions. Instead, non-POC particles were highly correlated with backscattering coefficients (R²>0.60). In conclusion, POC greatly impacts the phytoplankton pigment absorptions, while non-POC sediments strongly influence the backscattering properties in Taihu Lake.